نتایج جستجو برای: and evenness e

تعداد نتایج: 17333637  

پایان نامه :0 1371

in order to examine the ecological conditions and characteristics of fraxinus excelsior l. in the northern forests of iran 6 main areas as well as some miscellaneous ones , have been selected in the region respectively in : lomir2, shafaroud , park - e-noor , ahlam , alandan and noor.

ارزانی, حسین, برهانی, مسعود, بصیری, مهدی, زارع چاهوکی, محمدعلی, فرح‌پور, مهدی,

In order to investigate the effects of range management plans on species diversity, richness and evenness in Semirum rangelands, 52 sites (28 with treated plan and 24 without treated plan) were selected. The non-parametric indices for species richness (Margalof, Menhinick, Jacknife and counting method) and species diversity (Simpson, Camargo, Smith and Wilson and modified Nee) were compared in ...

Fariba Noedoost Mohammad Jankju

Rangeland ploughing and cultivation using dry land farming crops may be amajor reason for the destruction of natural resources in the semiarid and sub-humid regionswhich may significantly change the composition and reduce the stability of the affectedcommunities. In present research, an abandoned ploughed site was compared with a nearbyreference site in the semiarid rangelands of Baharkish, Quc...

2001
C. Ricotta E. De Zuliani G. C. Avena

Several evenness measures have been proposed for quantifying the distribution of abundance among community species, but none seems to be generally preferred. Since these measures have the common objective of summarizing community structure, they may be expected to be intercorrelated. In this paper, seven standard measures of evenness were calculated for 65 sample plots of ruderal vegetation wit...

2006
Margaret M. Bayer Tibor Bisztriczky

Cyclic polytopes are characterized as simplicial polytopes satisfying Gale’s evenness condition (a combinatorial condition on facets relative to a fixed ordering of the vertices). Periodically-cyclic polytopes are polytopes for which certain subpolytopes are cyclic. Bisztriczky discovered a class of periodically-cyclic polytopes that also satisfy Gale’s evenness condition. The faces of these po...

Journal: :Applied and environmental microbiology 2015
Lihua Niu Yi Li Peifang Wang Wenlong Zhang Chao Wang Qing Wang

To understand the relationship between elevation and bacterial communities in wastewater treatment plants (WWTPs), bacterial communities in 21 municipal WWTPs across China, located 9 to 3,660 m above sea level (masl), were investigated by 454 pyrosequencing. A threshold for the association of elevation with bacterial community richness and evenness was observed at approximately 1,200 masl. At l...

Journal: :محیط زیست طبیعی 0
حمزه جعفری سرابی دانشجوی کارشناسی ارشد جنگلداری دانشکده کشاورزی، دانشگاه لرستان، ایران بابک پیله ور استادیار گروه جنگلداری دانشکده کشاورزی، دانشگاه لرستان، ایران غلامحسین ویس کرمی کارشناس ارشد علوم گیاهی، سیستماتیک گروه جنگلداری دانشکده کشاورزی، دانشگاه لرستان، ایران جواد سوسنی استادیار گروه جنگلداری دانشکده کشاورزی، دانشگاه لرستان، ایران

forest reserves are one of the most important approaches in ecosystem management in iran. in order to determine the effects of reserve management on plants diversity (woody plants and ground flora) in three zones (core zone, buffer zone, and transmission zone of chamhesar pear forest reserve), we mapped land form units. then 18 main sampling units (20×50=1000 m2) distributed randomly were chose...

Journal: :Biological Journal of the Linnean Society 1996

The aim of this study was to evaluate the biodiversity ofplant associations in On Ebn-e-Ali Mountain in Tabriz and its relationship to various biodiversity indices. Four plant associations including 1) Noaea mucronata- Poetum bulbosa, 2) Noaea mucronata- Brometum tomentellus, 3) related to bush form as well as Poeto bulbosa-Brometum tomentellus and4) Brometo ...

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